Thermisation (also known as thermalisation) is a mild continuous heat treat-ment, immediately followed by cooling, such that the properties of the raw milk are almost unchanged while its bacterial flora, especially the psychrotrophic flora, is considerably reduced.
GULER Thermisation Systems are mostly preferred for the thermisation of cheesemilk usually to prolong its storage life prior to pasteurisation and/or cheese manufacture, while having a minimum effect on milk constituents and flavour.
Thermisation involves sub-pasteurisation heat treatments which range from 57 to 68 0C with holding times of 15±30 s. However, treatments of 63±65 0C for 15 s are usual. An upper limit of 65 0C for 20 s for thermisation means that >50% of alkaline phosphatase activity survives.This facilitates the determination of alkaline phosphatase activity as an indicator for subsequent pasteurisation of milk. Cooling and storage of the milk at 4±7 0C after thermisation is important to maintain microbial quality.
